Dull, remaining actors (8)
I believe the answer is:
overcast
'dull' is the definition.
(as in dull weather)
'remaining actors' is the wordplay.
'remaining' becomes 'over' (as in 'we ate them all but had one over').
'actors' becomes 'cast' (group of actors).
'over'+'cast'='OVERCAST'
(Other definitions for overcast that I've seen before include "The sky covered by dark clouds" , "Cloud-covered" , "Of sky, covered with cloud" , "Overacts, being gloomy" , "(Of weather) cloudy, dull" .)